Briquette and method of manufacturing briquettes



ugl, 1933- c. w. sEwELL 1,920,327

BRIQUETTE AND METHOD OF MANUFACTURING BRIQUETTES Filed May 6, 1925 f Q A Patented Aug. l, 1933 .PATENT OFFICE BRIQUETTE AND BIETHOD OF1\IANUFAC` TURING BRIQUETTESy Charles W. Sewell, Allentown, Pa.

Application May 6, '1925. Serial No. 28,423

My invention relates to means for and method of manufacturing briquettes..y

The coal mining industry, from the beginning, has been continuously presented with the problern of eliminating losses caused by the unavoidable production of unsalable, undersized particles of coal during the drilling, fracturing and crushing operations necessary to prepare the coal for market. Such small, undersized particles of coal are known in the trade as culm, silt, fines, or slack.

Technically trained fuel experts have spent years in study and research in an effort to discover satisfactory methods of utilizing such waste material, but so far such efforts have been unsuccessful, though involving the expenditure of large sums of money. Without referring-to the various methods that have been experimented with, .one method, in particular, appears to offer the most practical solution of the problem, namely, that of making the fines or culm into nuggets or briquettes. The disadvantages of the briquettes of the prior art are the smoke, soot, odor and obnoxious gases which result from burning the same. Moreover, many of the briquettes produced are not water proof, they do not stand weathering and they readily disintegrate in the re. An object of my invention, therefore, is to provide a briquette thatshall avoid the above-noted objections.

After a considerable period of experimental work and study, I have found that "smokeless, odorless and non-softening briquettes may be made With a tar binder either as a sole binding agent or in combination with other substances of vegetable or organic or inorganic nature, by an open flame, semi-carbonizing process, wherein the briquettes are subjected to such a temperature as to cause the same to ignite almost instantly upon their introduction into a specially designed furnace. The burning briquettes are then successively conveyed through one or more heated chambers of the furnace and subsequently discharged onto a conveyor operating in a cooling chamber.

Another object of my invention is to provide a process for the production of smokeless, odorlessv non-softening briquettes that shall be equally adaptable to the treatment of anthracite coal, bituminous coal and other carbonaceous materials.

Other objects and applications of my invention, as Well as details of construction and operation, whereby my invention may be practiced, will appear more fully hereinafter, when taken in connection with the accompanying drawing, wherein The single figure of the drawing is a sectional view of a furnace embodying my invention.

To facilitate the description and understanding of vmy invention, I shall now describe the various steps inthe manufacture of a smokeless, odorless, non-softening briquette from Lehigh anthracite coal. The binder employed for this type coal is coal tar and silicate of soda or dextrine emulsion. The tar preferably has a melting point of 90 degrees F. and the sodium silicate a density of Baume' 40 or 42, under which temperature and density .the tar and sodium silicate combine readily. However, the melting point of the tar may be as high as 170 degrees F. but when higher than 90 degrees F.. special heat must be provided to keep the same in a uid condition. The total binder used may be 10% of the weight of the coal, but it is preferably 8%. rl`his variation depends upon the fineness of the granulated coal, when sized through a screen of one-sixteenth inch round mesh and taking all passing the screen as is,-butfthe coal preferably consists of practically 20% through 100 mesh; 25% through 50 mesh; 20% through 30 mesh; and 15% through 20 mesh,

The binder and the coal are fed into a rotary paddle mixer and kneaded until the coal particles are coated with binder, whereupon the mixture is vpassed through a rotary press (not shown). The resulting briquettes are then discharged through a chute 1 onto a conveyor 2 which is positioned in one section 3 of afurnace 4. The furnace 4 is also provided with additional sections or chambers 5 and 6 and conveyors 7 and 8, respectively. The conveyor 2 is disposed in the upper portion of the chamberB immediately adjacent to an upper side 9 thereof, the latter being provided with an exhaust stack 11. The remaining chambers 5 and 6 are provided with similar exhaust stacks. The conveyor 2 extends between outer and inner walls 12 and 13,respectively, of the chamber 3. A re box 14 of conventional design is positioned in the base portion of the chamber 3, and it serves to heatsaid chamber 3 to such temperature as to cause the briquettes to ignite into a ame almost immediately upon entering the same. In other words, the briquettes quickly heat up to such point that the gases emitted therefrom ignite. There is thus a burning of the briquettes in open flame; resulting, in a semi-carbonization of the material of the briquettes but no ashing of the surface thereof since the flame does not come in actual contact with the briquette surface. For the particular type of coalunder consideration, this temperature is substantially between 900 and 950 quettc is thus partially carbonized. Experience b has shown that when the briquettes on the conveyor 2vhave become ignited into a flame, i. e., the gasesfrom the briquette have becomeignited;

the primary source of heat l14: may be dispensed with inasmuch. as theA necessary heat for the treatment of the briquettes is produced by the open ame combustion of 'the gases producedfrom saidbriquettes.` Thus the heat treatment of the briquettes in the chamber 3 becomes kan automatic one.

Should the heavy soot element of the briquettes i be not removed after passing through the heated chamber 3 and then require a further heat treatment, a r box 15 may be caused to heat vthe chamber 5 to the desired temperature. f A chute 16 extending through the wall 13 of the chamber 5 serves to convey the burning briquettes from the conveyor 2 to the conveyor 7. An upper edge 17 of the chute 16 is positioned immediately adjacent to the conveyor 2 in order to prevent such briquettes as may adhere thereto from being carried around to the underside of the conveyer. The advantages of a sectional conveyor system of the type shown inthe drawing are apparent. For example, it tends to prevent the briquettes from sticking to the conveyors by periodically dropping the briquettes from one conveyor to another, as well as simplifying the construction of the conveyor.

`The hardening of the briquettes` due to the presence of sodium silicate or dextrine prevents the breaking of the same upon the passage from the conveyor 2 to the conveyor 7. A chute 18 is mounted in a second Wall 19 of the chamber 5, and it serves to convey the briquettes to the conveyor 8 in the chamber 6. This chamber serves to cool the briquettes below the naming point, say to approximately 800 degrees F., whereupon the briquettes may be discharged through a chute 21 which is positioned in'a remaining wall 22 of the cooling chamber 6. The chute 21 is operatively associated with a conveyor 23 which leads to further cooling means (not shown), whereupon the briquettes may be cooled and stored. A briquette resulting from the foregoing process has been found to be smokeless, odorless, serni-carbonized and vto have a relatively high volatile content.

My invention -also contemplates the manufacture of briquettes from non-coking bituminous, strong-coking bituminous coal and gaseous bituminous coal. nous coal is used, the bindei' comprises approximately 25% tar and '75% sodium silicate. The percentage of the binder to the coal is 10% or less according to the sizing of the coal. The

i treatment in the furnace 4` is substantially the same` as that just described for the anthracite coal, the time in the chamber 3 being approximately fteen minues. As will be apparent, the tar constitutes the coking medium for the noncoking coal and the silicateof soda adds sufficient strength to the raw coal briquette to hold When the non-coking bitumii the same together until the desired carbonization is completed. The sodium silicate also serves to lower the fusing point of the coal and to prevent the disintegration of the briquettes in the re before they are completely burned to ash.

The binder for the strong-coking bituminous coal may comprise a half and half solution of sodium silicate and water.. The4 percentage of binder to coal is 10% or less according to the sizing of the coal. The natural tar-content of the coal in the present materialis the coking element and the solution of sodium silicate cons titutes the preliminary binder.

The gaseous bituminous coal has a high tar content, so that it tends to soften and run under r moderate heat.

In accordance with my invention, such coal is mixed with such other coals as non-coking bituminous or anthracite coal, or it ismixed with such inorganic substance as clay. When coal is used as a mixture as, for example, anthracite fines, a half and half proportion has been found satisfactory. When clay yor 'other inorganic substances are used. the proportions are approximately 10 to 15% inorganic substance and the balance gaseous bituminous coal. The clay or inorganic substance should be dried, pulverized and preferably sized to pass oney sixteenth inch round mesh screen. The binder used witheither of the clay and coal mixtures or a mixture of different coals is silicate of soda, the percentage of binder to coal varying from 4 to 8%. As abovenoted, the foregoing examples are given for purposes of explanation and illustration and are susceptible to various changes necessitated by the various varieties of coal and the different grades in each variety.

vWhile I have described certain embodiments of my invention in detail, and While I have pointed out certain of the most obvious principles and purposes thereof, I do not intend that the language employed in the following claims shall be limited to the precise features described, but I intend that the claims shall be construed to cover all combinations which are fairly included in the language thereof,.when read in connection with the prior art, regardless of the details and functions mentioned in the description or illustrated in the drawing.

, I claim:

l. The method of producing semi-carbonized briquettes, which` comprises initially heating from a primary source the briquette to the point of ignition, and thereafter conveying the burning briquette through a series ,of chambers having gradually `decreasing temperatures.

2. Ingthe manufacture of coal,v the process which comprises briquetting coal with a binder under pressure, transferring the briquetted material to a chamber, and moving said material through said chamber while subjecting the material to hot gases, the time of exposure of the material to said gases being substantially `between ten and thirty minutes.

3. In the manufacture of smokeless fuel. the process which comprises briquetting bituminous coal with a suitable binder under pressure, transferring the briquetted material to a conveyor passing substantially horizontally through a heated chamber, and subjecting said material to hot gases, the time of exposure of said material to said hot gases being substantially between ten and thirty minutes.

CHARLES W. SEWELL. 

